Switch and signal control system for railroads



Dec. 9,194l.

C. A. PICKELL SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed July 6, l1959 l1 Sheets-Sheet l BY www INvE @l fb.

ATTORNEY Dec. 9, 1941. c. A. PICKELI.

` SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed July 6, 1939 11 Sheets-Sheet 2 FIG. ZA.

m r "am" na lNvENToR BY ./w ATToRNE Dec. 9, 1941. c. A. PICKELI.

Filed July 6, 1939 FIG.. 2.6. I

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SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 11 sheetssheet 1o Filed July e, 1959 AT TORNE'Y Dec. 9, 1941. c. A.- PICKELL SWI'CH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 11` sheets-sheet 11 Filed July 6, 1939 Patented Dec. 9, 1941 SWITCH AND SIGNAL CGNTROL SYSTEM FOR RAILROADS Clark A. Pickell, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application July 6, 1939, Serial No. 282,999

(Cl. 24S-2)vv 5 Claims.

This invention relates toY switch` and signal control systems for railroads, and it more particularly pertains to the control, by use of, a code type communication system, of switches and signals remotely located from an entrance-exit type control machine at a control oflice.

An entrance-exit type control machine is generally provided with a control panel within. convenient reach of an operator, upon which is constructed a miniature track diagram of the track layout in the field for which the machine is provided. The entranceand exit ends of routes in the track layout are defined by the location of Wayside signals, each. .route extending from an entering signal to lanother signal for governing tramo in the same direction, or to the limits of the track sections governed by the control machine, as the case may be. Control buttons, or equivalent contactors, for the designation by an operator of each entrance and exit point are provided on the control panel along the miniature track diagram at points corresponding to the respective entrance and exit ends of each route, and suitable indication means is provided along the track diagram for conveying to an operator an indication as to which routes are established, the condition of occupancy of the various track sections, andthe condition of the signals.

In accordance with the present invention such a control machine is connected by means of a suitable code type communication system, such, for example, as the communication system shown in the patent to Judge et al., Patent No. 2,082,544, dated June 1, 1937, with an entranceexit type of vswitch and signal control system at a remote track layout which can be, for example, of the type shown in the patent to A. Langdon, Patent No. 2,148,865, dated February 28, 1,939, and in the application of Wight and Langdon, Ser. No. 245,384, filed December 13, 1938 now U. S. Patent 2,219,502, granted Oct. 29, 1940.

i The switches and signals relatively close to each other, together with the apparatus for their control, constitutes what is -conveniently called a field station, and each eld station is subdi- I'- which for thek transmission of controls from the control oiiiceito the eld are called control cycles,and others for the transmission of indicationsof `the devices at the eld stations to the control oice are called indication cycles, each cycle being characterized by the energization of a line circuit extending between the control ofy ce and the eld stations with a series of time spaced electrical impulses. It can also be provided by duplex operation that indications can be transmitted under certain conditions at the same time in which controls are being transmitted from the control oice.

Each control cycle is composed lof a series of time spaced impulses forming a complete composite code. The rst part of that code is used to identify the particular field station for which the controls are to be transmitted; the second part of that code is used to identify the control station for which the controls are intended; and thelast part of' that code is used to dene in theeld the control designated in the control oflice for an entrance or exit point or track switch.

An object of the present invention is to vprovide that only one entrance or only one exit point canhave its code transmitted during one control cycle, thus requiring the transmission successively Vof two cycles of operation for the complete establishment of any route in accordance with the designation of the entrance and exit ends of that route. An advantage of such a mode of operation is that transmission of a cycle for deiining an exit point occurs subsequent to the transmission of a cycle for defining an entrance point which allows a sufficient period oi time for the conditioning of certain relays in the eld which are required for the proper reception and storage of a code dening an exit point for that route.

, Another objectof the present invention is to provide a simple means for rendering the transmission of controls effective upon actuation of the contact means on the control panel for designation of controls to be transmitted, such initiation of the communication system being effective only after the contact means causing such initiation has reached its new operating position. In other words, the initiation of the communication system for the transmission of controls is eiective only when an operator has actuated a contactor on the control panel to a new operating position, thus providing assurance that the controls to be transmitted are designated before initiation of the system becomes effective.

Another object of the present invention is to provide a means whereby the establishment of each route in the field is effective responsive to the designation by an operator at theV control oiiice of the extreme ends of that route only, even if there are intermediate signals included between the route ends designated. The establishment of a route including one or more intermediate signals responsive to the designation of the extreme entrance and exit ends only of such route is called, for convenience, through route or end-to-end control.

Another object of the present invention is to provide that the designation of either an entrance or an exit control by an operator initiates the system into a cycle of operation for the transmission of such control, and as long as the respective entrance and exit points for each route are designated in their proper order, (the entrance end of each route designated prior to the designation of the exit end of that route) such order is always maintained in the transmission during successive control cycles for respective entrance and exit controls, even if both the entrance and exit ends of a route are designated by an operator at a time when the communication system is not immediately available for the transmission of such controls.

It is believed that other objects, purposes and characteristic features of the present invention 3f, will be more readily understood upon reference to the accompanying drawings and as they are apparent at various points in the description of the present invention.

In describing the invention in detail, reference is made to the accompanying drawings in which corresponding parts are designated by correspending reference characters, in which those parts having similar features and functions are designated by like letter reference characters which are generally made distinctive either by distinctive exponents or by preceding numerals, and in which:

Fig. 1 illustrates diagrammatically, the general organization of a system provided in accordance with the present invention;

Figs. 2A, 2B and 2C,` when placed side by side, illustrate the means provided in the control ofiice for setting up codes to be transmitted to the field in accordance with the actuation of buttons and levers on the control machine;

Fig. 3 illustrates the means provided at the control oiiice for the stepping impulsing of the line circuit, and the reception of indications for the communication system used in this embodiment of the present invention;

Fig. 4 illustrates the means provided at one of the field stations for the reception and decoding of codes transmitted from the control oiiice, and also illustrates means provided at such iield station for the transmission of indications to the control oirice;

Figs. 5A and 5B, when placed side by side, illustratecircuit means by which the decoding of code lmessages is transferred upon execution to switch and signal application relays;

Figs. 6A and 6B, when placed side by side, illustrate the track layout for which the control apparatus illustrated in Figs. 2A, 2B and 2C, is provided, together with an entrance-exit type of 70 self-selecting circuit network system for establishing the various routes in accordance with the controls designated by an operator in the control cnice; and

Fig. 7 illustrates certain typical circuits relative 75 to the control of the switches and signals at the various control stations.

Reference is made from time to time during the description of the present invention to relays and devices of a similar nature by use of letter reference characters associated with such parts Without their preceding numerals and exponents. It is to be understood that such a reference applies to any parts designated in the drawings by letter reference characters which are similar except for preceding numerals and exponents.

The various parts and circuits constituting the embodiment of the present invention have been shown diagrammatically and certain conventional illustrations have been employed for the purpose of facilitating the explanation of the present invention and for the purpose of simplifying the drawings, rather than for illustrating the speciiic construction and arrangement of parts that would be employed in practice. Thus, the various relays and their contacts are illustrated in a conventional manner, and symbols are used to indicate connections to the terminals of batteries or other sources of electric current instead of showing all of the wiring connections to such terminals. In order to illustrate more clearly the arrangement of circuits employed in accordance with the present invention some relays have been shown in more than one drawing, and some relays have the circuits shown for their different windings on different drawings, the corresponding relays throughout the different drawings being readily identiiied by like nomenclature.

The symbols (-1-) and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of direct current, and the circuits with which those symbols are used always have current flowing in the same direction. If alternating current is used in place of direct current, the particular symbols shown are to be considered as relative instantaneous polarities.

Apparatus Track layout- With reference to Figs. 6A and 6B, the track layout chosen for the embodiment of the present invention consists of a main stretch of track to which are connected two other tracks by means of the track switches ZTS and STS respectively.

Signals are provided for governing traiiic through the track layout in each direction, signals 4, 4C, 5 and 6 being provided for governing east bound traiiic to the right, and signals 1, 8 and 9 being provided for governing west bound traii'ic to the left.

The signals are illustrated as being of the color light type having individual color lamp units, the top lamp providing a green clear indication, and the lower lamp providing a red danger indication for each signal. It is to be understood that a yellow indication for caution can as well be provided, in `accordance with the requirements of practice, and that other types of signals such, for example, as semaphore and search light signals can as well be used.

The track switches ZTS and STS are provided with switch machines ZSM and 3SM respectively which provide the power operation of those track switches in accordance with the positions of the track switches required. Various types of switch machines can be used, such, for example, as the type disclosed in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. Each switch machine is assumed to have included therewith suitable -overload protection devices and other control apparatus commonly employed in the control of the switch machine motors, such as is shown, for example, in the patent to W. H. Hoppe et al., Patent No. 1,877,876, dated September 20, 1932.

The track layout is divided into two track sections 2T and 3T which are provided with track circuits `in the usual manner for control of the track relays ETR and 3TR respectively. It is to be understood that the track switches ZTS and BTS are properly bonded to provide fouling protection in the usual manner.

Each track switch has associated therewith a point detector relay WP of the polar neutral type energized with one polarity when that particular track switch together with its switch machine is locked in a .normal position and energized with the opposite polarity when that track switch and its switch machine are locked in a reverse position. Each relay WP is deenergized whenever its track switch and/or its switch machine are unlocked or out of correspondence. Such control of each relay WP is provided by contact selections which include contacts ci a point detector contact mechanism of the type shown, tor example, in the patent to C. S. Bushnell, Patent No, 1,517,236, dated November 25, 1924.

Control Machine-'The :control machine used in accordance with the present invention can be of the type shown, for example, in the patent to J. F. Merkel, Patent No. 2,145,798, dated February 28, 1939, in which a vertical control panel is provided within convenient reach of an operato-r. Upon the control panel is constructed a miniature track :diagram to correspond with the track layout in the field lfor which the System is pr-ovided, and suitable indicator lights are -disposed along the track diagram to provide suiicient indications to keep an operator well informed as to the various conditions existing in `the field pertinent to the condition of occupancy of the various track sections, the routes established, and the condition of the various signals. Inasmuch as this invention is primarily related to the control of the `switches and signals in the eld in accordance with the actuation of control devices by an operator at the control office, such indications have not been shown in this 'disclosure except for one indicator lamp XCH-E (see Fig. 2B), for the .purpose of simplification, but it is to `be understood that the indications `are provided in a .suitable manner .such as is shown,

for exam-ple, in the application of R. M. Phinney,

Ser. No. 216,459, irl-led June l29, 1938.

For designation of the entrance end of each route, a control button NB is provided on the control panel at a point in the miniature track diagram corresponding to an entering signal for that route in the field. That is, vfor example (see Fig. 2A), the entrance button NB is provided on the miniature track diagram at a point corresponding to the location of signal li (see Fig. 6A) at the tra-ck layout in the eld. 'Each of the entrance buttons NB is of the push-pul1 type, and is biased to a center ,position with respect to push-pull operation, and, where yanother operating position is required for the button, such as is :required for the `control lof va call-on signal, f

the button can be rotated from its vnormal center position to an operating position in which it will remain until manually restored to its normal position. Ille construction of a control butt/on to provide rsuch distinctive positions can be provided in any suitable manner, such, for example, as that shown in the application of J. F. Merkel, Ser. No. 158,720, iiled August 12, 1937, now U. S. Patent 2,223,126, granted Nov. 26, 1940.

Each of the exit buttons XB is used for designation of the exit end of a route and is disposed on the miniature track diagram at va point corresponding to the exit point at the track layout with which it is associated. Each exit button XB is of the self-restoring type, having an operating contact closed when the button is depressed.

It is to be understood that other types of contaetors than the specic types shown and described in this embodiment of the invention can be provided, in accordance with the requirements of practice, and that the entrance and exit buttons NR and XR respectively for each signal location can have their contacts combined into one butto-n providing the required number of distinctive operating positions, and it is to be further understood that a single button .can be used for each route end for designation of both entrance and exit points in combination With circuit means for distinguishing between the actuation of a control button for the designation of an entrance or an exit point such as is shown, for example, in the application of R. M. Phinney, Ser. No, 216,459, iiled June 29, 1938.

An auxiliary switch control lever SML is provided .on the control panel for each of the track switches so that an operator -can cause the positoning of that track switch irrespective of `the system for the .establishment .of routes in aocordance with .the designation of entrance and exit points. Each auxiliary vswitch .control lever SML has a center neutral position in which it is ineffective for governing the operation of its associated track switch, an upper operating .position in which it causes the operation of its track switch to a reverse position, and a lower operating position in which it causes the operation of its track switch to a normal position. Each lever SML is maintained `in either of its three operating positions until actuated to .another position by an operator.

Control `office Malaya-At the control oilice entrance relays NR are responsive to the designation .of their particular entrance points by an operator, and, when rpi-cked up, they are main.- tained energized until a cycle of operation of the communication system is vcompleted for transmission of controls to the eld in .accordance with such entrance designation. For a similar purpose a relay CNR .is provided for each call-on signal governing entrance lto :each route. A change relay NCH is provided for each entrance point, and is picked up when the designation of that entrance point is effected to initiate the system into a cycle of operation.

Upon designation of an exit point by an operator an exit Ychange relay 'XCH is energized to cause the transmission of controls for dening that particular exit point in .a manner which corresponds with the initiation of `the system in accordance with the energization of each entrance change relay NCH.

As a part of the communication system certain `relays are provided in the control ofiice which correspond in `character and vfunction to relays bearing similar .nomenclature shown in the above mentioned patent to Judge et al. Patent No. 2,082,544, .dated YJune 1, v1937, and, in view of the fact that a detailed description of such relays Vand their control circuits is shown in that in accordance with that Judge Aet al. patent,

relays CHP, CDS, CD, C, FC, NC, PC, E, EP, F, FP, 2F13, SA, 2SA, DV, MF', NB, VP, IV, 2V, 3V, 4V, 5V, 6V, lV vand LV are provided at the control oflice.

A relay XCI-IP is provided in the control office Afor the purpose of preventing from becoming effective the designation of entrance and exit points for a second route when the entrance and exit points designated for a rst route have not yet been transmitted. Such relay XCI-lP is normally energized and is dropped away whenever a change relay XCH is picked up for an exit point designated. As a means for cancelling any controls designated which have not yet been transmitted, a cancel button CAN is provided which, when depressed, causes the restoration to normal of the relays associated with the initiation of the communication system.

Field station relays-. The eld station relays (see Fig. 4) include certain relays essential to the communication system such as relays F1, FP1, S01, SOSl, SA1, SB1, PB1, PF1, IV1, ZV1, 3V1, 4V1, 5V1, 6V1, 1V1, LV1 and VP1.

A bank of decoding relays composed of relays NS for decoding' negative impulses and PS for decoding positive impulses is provided at the field station, one PS relay and one NS relay being provided for each stepy in the eld used for the reception of control'and control station impulses. The relays PS and NS are picked up during the reception of controls as they are received, and those relays are maintained energized when picked up until after execution of the controls thus decoded at the end of that cycl'e of operation.

Each control station in the iield has a control station relay ST which is energized during a control cycle when the controls of that cycle are for that particular station. Thus, for example, if the controls designated are for the route end at signal 5, the station relay IST (see Fig. 5B) is picked up to correspond with the controls transmitted for station I as shown in Fig. 1.

An entrance relay NR1 is provided for each entrance point and an entrance relay CNR1 is provided for each entrance point that has a call-on signal. The en-trance relays NR1 and CNR1 are energized during the execution period at the end of the control cycle in accordance with the designation of corresponding entrance points at the control cnice. Such entrance relays are maintained energized when once picked up dependent upon the condition of occupancy of various track sections in the ield and/or dependent upon the position of the stop relay B, which can be energized responsive to the designation in the control oice by an operator for the restoration of a particular signal to stop or a particular entrance relay to its normally deenergized position.

A relay XZ having slow drop away characteristics is provided for each exit point in the iield, and it is energized momentarily at the end of a control cycle for designation of its exit point to cause the picking up of an exit relay XR (see Figs. 6A and 6B), such exit relays im being energized only if a route is available between that -eXit point and an entrance point which has been designated on a prior cycle of operation of the communication system.

A route is selected in the eld in accordance with the selective energization of normal and reverse switch control relays N and R which have their control circuits selected in accordance with relays Y which are energized for track switches trailed normal in an available route from each designated entrance point.

Response to the picking up of a normal relay N or a reverse relay R for each track switch, a polar neutral switch control relay WZ (see Fig. 7) is energized with the proper polarity to cause the positioning of its track switch if such positioning is safe and proper as determined by the lock relays L and LS, the energization of such klock relays for allowing the positioning of the track switch being dependent upon the route and detector locking.

When each of the track switches has completed its operation in accordance with designated controls, a correspondence relay NCR or RCR, dependent upon the position of the track switch, is energized, and the lock stick relay LS for that track switch is dropped away to close a branch of the circuit network for the energization of a relay G provided for each signal for governing the indications such signal is to display.

In accordance with the principles of the selfselecting network system they have been set forth in the application of S. N. Wight and A. Langdon, Ser. No. 245,384, led December 13, 1938, a relay XP is provided for each intermediate signal that can be included between extreme ends of a route designated for the establishment of a route in accordance with the system of endto-end control.

Having thus considered the apparatus provided in accordance with the present invention and its general application, a more specific description of the principles of the system and the mode of operation will be hereinafter set forth upon considering various typical conditions of operation of the system.

Operation Inasmuch as the communication system used in accordance with the present invention is substantially as shown and described in the patent to Judge et al., Patent No. 2,082,544, dated June 1, 1937, reference can be made to that patent for the specific description of the communication system omitted in the present disclosure. The general operation of the communication system will, however, be hereinafter pointed out in a manner believed suicient for an understanding of the present invention, and such improvements in the communication system as are provided by the present invention will be specically described.

Communication .sytem generaZ.-As has already been pointed out, the communication system is operable through various cycles of operation, each cycle being composed of a series of electrical impulses. The impulses are time spaced and of a selected polarity, such impulses being impressed at the control oice upon a line circuit extending from the control oflice to the eld stations. The control line circuit to which the impulses are applied is composed of two line wires of which, for the purpose of describing the present invention, one wire is called the control line and the other wire is called the return line. The control line and return line wires are connected at the most remote iield station and the control line wire 20 (see Figs. 3 and 4) includes in series a three-position polar relay E at the control office and a similar relay F1 at the eld station illustrated in Fig. e, and a relay F (provided with a proper exponent) for each of the other iieldv stations included in the system For the purpose of referring from time: to time to the polarity of the line circuit refer-v ence is made to the positiv-e or negative energize.'- tion of such circuit, and that reference is to be understood as the; connection of the positive or` negative battery terminal respectivelyl to the side: of the. line circuit at the control omce: including the control line Wire 2li.`

The organization ofk the. communication sys tern is such that when it is inactive, most ci its relaysV are normally deenergized and: the system is considered in general at such time. to be in aA period of rest, The initiation of al control cycle atY the control otcer upon designation by an operator of a control to be transmitted, causes energization of the` line circuit: for a, rst impulse with a selected polarity,V dependentl upon the code to be transmitted. Such initial: energization of the` line circuit is known as the conditioningperiodi in which certain normally deenergized re lays at the control office and at each field station are energized to condition the system for the purpose of communicating` the controls riesig` nated. After such conditioning hash been com-- pleted an impulsing relay is picked upat. the control oince to cause the rst period ot dicenergization of the line circuit during the. cycle, commonly known as the first oii'period During. such off period the iirst of the stepping relays V is picked' up at the controi oice and ateach field station that remains in communication with the control cnice, and the picking up of sucia` a stepping relay causes the dropping'. away of the impu-lsing relay at the control oiice which closesV the line circuit for the second period, of energization during the cycle, which isconveniently called the rst on period. Thus, the com munication system is operated step-by-step through each cycle, one stepping relay being picked up during each on period, and an element of the code being applied by means of selected polarity, as Wi-ll hereinafter be pointed out, to the line circuit during each on period. After the stepping, during a cycle of' operation, has been completed, they system entersa clearing-outl period, during which time the controls decodedI at the field stationselected for theI reception of controls, are executed, and during which restoration of the relays to a period of rest is eiiective.

Suitable lockout means is provided at the control office whereby the transmission of controls selected for one cycle of operation cannot be in-l terrupted by the designation of other controls to be transmitted.

The stepping at each of the field' stations continues to be effective during a control cycle only so long as the predetermined code to which that leld station is responsive for field station selection corresponds with the code characters impressed upon the line circuit at the control: cnice. Thus, it is obvious that the series-off impulses at the control oii'ice carries' a message which, through the process of elimina-tion, maintains only one particular field station incommunication with the control office forthe recep tion of the remainder of the impulses' of that cycle.

Normal conditions-With reference to Figs; 2A, 2B, 2C and 3 thel relays of the system at the control oli-ice are all illustrated under norma-i 7 conditions toy be deenergized. with the exception of relays` ZCI-I and XCHP- shown in Fig. 2B. Relay 20Hv is normally maintained energized by the energization of a stick; circuit closed from (-l-i, a circuit including; back contact 22. of relay 2CD iront contact 23 of relay 20H, and lower Winding ot relay ZCI-E, to (-l. Relay XCHP is normally maintained energized by the energization of a circuit closed from through a circuit including back contact 2-4 of reiay 5=XCIL back contact 25 of relay XCI-I, a back contact oi a relay XCH for each of.' the other exit points: as represented on the drawing by an,X,. and winding of relay XSI-IP, to

At, the neld station. under normal conditions, the relays associated with the communication system arc deenerg-ized with: the. exception of the change relay which is normally maintained energized. its deenergization by a change the position of one of the devices to be indicatedV causes the; initiation of an indica..- tion cycle- The relays associated with the: self-selecting network. in the el'd and' the control of the switches and signals as shown in Figs. 6A, 6B and 7 are normally deenergized with the exception ci the track relays TR, the lock. relays L and LS, the correspondence relays NCR.. The lock relay EL (see Fig,A 7) is normally' maintained energized' by a circuit closed from through a circuit including front contact 26: of relay 2ES', front contact 21 of relay ZTR, front contact 2'8 of relay' 2WS Winding or relay 2L, andr iront contact 2% ofl relay 2L, to G-i. Relay 2LS is normalily energized by a: circuitr closed from (+L through a circuit including front contactAA 3U oi relay 2L, backcontact 3=I'= of relay ZWZ, and Winding of relay ZLS, to The correspondence relay ENC-R is norm-ally energized by a circuit closed from (-1-) through a circuit including back Contactl 32 of relay 211i,a Winding: of relay 2NCR, polarcontact 3'3:t of relay ZWP in a right hand position, and front contact 34 of relayl ZWP, to

The track switches areassumed to be in the position required for the last route: established, which, for the present disclosure, hasA been assumed to be a, through route on the main track.

Initiation of the system-When an operator wishes to designate controls to be transmitted to a eld station, he first checks. his indicator lamp which, if extinguished indicates that er1- trance' and exit controls designated' previously have been. transmitted, and then he proceeds to designate the controls which he wishes to have transmitted to a field station. He mayv designate controls forrestoration or control for the-switches when. the: indicator lamp XCHE is illuminated, but he must not, designate entrancey or exit controls unless the indicator lamp is extinguished.

To consider the designation of a particular typical typev of a control to be; transmitted, assume that ran operator designates an entrance point at signal 5A fora route toVA be established by the depression of button SNfB, when the normal conditions of the system exist as they have been shown and described.. The depressionot button SNB causes the energization ot the entrance re lay ENR', andi the pink-ingr up off relay ENR causes the picking up. of' the relay ENCI-F for the initiationof the control cycle. Relay' SNCB? causes the picking up of relay CHP,v and' relay CHP in' piek"- ing up causes the energization of relay Ci. The relay SCD is picked' up after relay C", and upon picking up, it closes it's stickcircuit which includes rin series relay CDS which is picked up at that time. When relay ECD is picked up, the relay PC is energized to cause the positive energization of the line circuit for the conditioning period of a control cycle to be transmitted. Each ofthe above relays energized at the start of the control cycle is maintained energized throughout the cycle with the exception of relay NCH which is dropped away upon the picking up of relay ECD.

To consider in detail the circuits by which the above mode of operation is effected, relay ENR is energized when kthe button BNB is depressed by a circuit closed from (-1-), through a circuit including contact 36 of button 5NB closed in a depressed position, and upper winding of relay 5NR, to Upo-n the picking up of relay 5NR, a pick-up circuit is closed for relay 5NCH from` (-1-), contact 36 of button 5NB in a depressed position, front contact 31 of relay 5NR, upper winding of relay 5NCH, wire 38, and front contact 39 of relay XCHP, to A stick circuit is closed for relay 5NCH upon the picking up of that relay from (-1-), through a circuit including back contact 40 of relay 5CD, front contact il of relay 5NCH, lower winding of relay 5N CH, wire 42, and normally closed contact 43 of cancel button CAN. Such stick circuit maintains relay 5NCH energized until relay 5CD is picked up or the cancel button CAN is depressed.

When relay 5NCH is picked up, a stick circuit is closed for relay 5NR from (-1-), through a circuit including front contact 'I0 of relay 5NCH, front contact H o-f relay SNR, and lower winding of relay ENR, to Energy is alsoapplied to that stick circuit at front contact 40 of relay ECD to provide that relay 5NR is-maintained energized until the end of the cycle for the transmission of the controls selected by that NR relay. The stick circuit is maintained closed. because relay .'iNCH is maintained picked up until after relay CD is picked up.

The picking up of relay 5NCH causes the picking up of relay CHP by the energization of a circuit closed from (-1-) through a circuit including back contact M of relay SA (see Fig. 2C), back contactil of relay FC, upper winding of relay CHP, wire 455, and front contact 4l of relay 5NCH, to Relay CHP is maintained energized until the end of the cycle by a stick circuit closed from (-1-), through a circuit including back contact 48 of relay LV (See Fig. 2C), front contact 49 of relay CHP, and lower winding of relay CHP, to Energy is also applied to that stick circuit at back Contact 50 of relay EP to prolong the period in which relay CHP is maintained energized in case relay LV is picked up to open back contact 48 before the end of the last impulse.

Upon the picking up of relay CHP a circuit is closed to cause the picking Vup of relay C from (-1-), through a circuit including .back contact 5I of relay SA, front contact 52 of relay CHP, and winding of relay C, to A stick circuit is closed for relay C when that relay is picked up to Nmaintain it energized throughout the cycle from (-1-), through a circuit including back contact 53 of relay 2SA connected in multiple with front contact 5l of relaySA, front contact 54 of relay C, and winding of relay C, to That stick circuit is maintained closed throughout the cycle because relay ,SA is picked up kprior tothe energization of its repeater relay 2SA, and both relaysare maintained picked up because of their slow action throughoutV the cycle of operation.

Upon the picking up of relay C, relay 5CD is picked up by. the energization of a circuit closed from (-1-), through a circuit including back contact 48 of relay LV, back contact 55 of relay 2SA, front contact 56 of relay C, back contact 51.0f relay CDS, wire 58, front contact 59 of relay 5NCH, lower winding of relay 5CD, wire 42 and normallyclosed Contact 43 of cancel button CAN, to When relay 5CD is Apicked up, a stick circuit is closed for that relay including the Winding of relay CDS, from (-1), through a circuit including front contact 60 of relay CHP, Winding of relay CDS, wire 6|, front contact 62 of relay 5CD, upper Winding of relay 5CD, wire 42, and normally closed contact 43 of cancel button CAN, to The picking up of relay CDS prevents the picking up of any other CD relays during that cycle of operation by opening the circuit for such relaysat back contact 51.

Upon the' picking up of relay 5CD energy is applied to the relay PC for the energization of y the line circuit at the beginning of the conditioning period in a manner which will hereinafter be pointed out when considering the polarity selection of the impulses to be applied to the line circuit.

The picking up of relay 5CD causes the release of relay 5NCH which is sufciently slow in dropping away to insure the establishment of a stick circuit for relay 5CD.

The means heretofore described for the initiation of the system in accordance with the depression of the entrance button SNB is to be considered typical of the initiation provided but not shown and described in detail for the entrance points at each of the signals 6, l, 8 and 9 (see Figs. 6A and 6B). The initiation of the system in accordance with the designation of signal 4 as an entrance point is effected in a much similar manner, except that an operator can select by the distinctive position to which he actuates the button 4NB as towhether the route established having an entrance point at signal 4 is to be automatically restored in the field upon the acceptance of the entering signal to that route by an approaching train or whether a callon indication is to be provided for that entering signal without providing the stick feature used when the call-on signal is not designated.

If an operator depresses button 4NB (see Fig. 2A) at a time when the normal conditions of the system exist as they have been described, relay 4NR is picked up, and its energization causes the picking-up of relay 4NCH which is turn causes the initiation of the system in a manner similar to that which has been described responsive to the depression of button ENB.

The depression of button 4NB causes the picking up of relay 4NR by the energization of a circuit closed from (-1), through a circuit including contact 8'2 of button 4NB closed in a normal position with respect to rotation of the button, contact8,3 of button 4NB closed with that button in a depressed positionhupper winding of relay .4NBI and back contact 8l of relay CNR, to The picking up of relay INR causes the establishrnent 'ofr a stick circuit for that relay similar to the circuit which has been described for relay 5NR, and also causes the picking up of relay 4NCH for the initiation of a cycle ,by the energization of acircuit closed from (-1-), through a circuit-including contact-82 ofbutton 4NB in a normal position with respect to rotation, contact 83 of button ANBfclosed in a depressed position, front contact 66 of relay ANR, winding of relay ANCH, Wire 38, and front Contact 39 of relay XCHP, to The picking up of relay ANCI-I causes the initiationv of acycle in a man-A ner similar to that described in connection with the picking up of relay NCH.

If, however, an operator desires to designate an entrance point at signal AC in such a manner as to cause the clearing of call-on signal AC (see Fig. 6A) he rotates theV button ANB (see Fig. 2A) inv a counterclockwise direction to an operating position, rather than depressing the button, and such rotation closes contact 6A of button ANB which establishes a pick-up circuit for relay ANCI-I, closed from (-1-), through a circuit including contact 6A of button ANB in a counterclockwise operating position, back contact t5 of relay ANCR, back contact 66 of relay ANR, upper winding of relay ANCI-Lwire 38, and front contact39fof relay XCI-ll?, to

Upon the picking up of relay ANCH, a circuit is closed to .cause the' picking up of relay ACNR, from (-1-), through a circuit including contact 6A of button ANB in a counterclockwise operating position, front contact 6l of relay ANCH, back contact 68 of relay ANR, and winding of relay ACNR, to When relay ACNR is picked up a stickA circuit is closed for that relay from through a circuit including contact 3A of button ANB. in a clockwise operating position, front contact 69 of relay ACN'R, and winding of relay ACNR, ,toA Such stick circuit provides for theV continued energization of relay ACNR during the dropping away of relay ANCH, which is effected upon the .picking up of relay ACD at the start ofacontrollcycle in a manner similar to that4 described for the relay SNCH. After relay ANCH is droppedl away, a second stick circuit is closed for relay A'CNR for the purpose of maintaining -that relay energized until another control has been designated by an operator to cause the picking up of relay ANCH, from (-l-), through a circuit including front contact 12 of relay ACNR, back contacts 61 of relay ANCH, back contacts 68 of relay ANR, and winding of relay ACNR, to The maintaining of relay ACNR energized in such manner is essential to the transmission of a code for the restoration of a route established having its entrance point at signal A for the clearing `oi the call-on signal AC as will hereinafter be pointed out in detail. Thus, the relay ACNR is picked up when an operator rotates the button ANB in a counter clockwise direction to an operating position, and that relay is maintained energized until the relay ANCH is picked up in accordance with the designation of another control Yto be transmitted to the field station.

The picking up of relay ACNR opens the pickup circuit just described for relay ANCH at back contact 65 to prevent the subsequent energization of relay ANCH except after the button ANB is restored to its normal position with respect to rotation.

Having thus described how an operator can initiate the system for the transmission of a control code appertaining to a designated entrance point, consideration will now be given to the means for initiating the transmission of a control code for defining an exit point for a route in accordance with the designation of such a control by anv operator upon the depression or an exit button4 Thus, for example, assume that an operator wishes to designate an exit point for a route to be established at signal 5, after having designated an entrance point for that route by the depression of an entrance button such as button TNB. To designate the exit point at signal 5 an operator depresses button EXB, and the depression of that button causes the picking up of relay SXCH (see Fig. 2B) by the energzation of a circuit closed from through a circuit in cluding contact 13 of button BXB closed in a depressed position, upper winding of relay SXCH, wire 38, and front contact 38 of relay XCI-IP, to The picking up of relay SXCH causes the dropping away of relay XCHP by the opening of the normally energized circuit for that relay at back contact 2A. Relay XCHP is sufficiently slow in vdropping away to insure the establishment of a stick circuit for relay BXCH before opening the pick-'up circuit just described, closed from (-I-l, through a circuit including back contact 'IA of relay SXCD, front contact 15 of relay SXCH, lower winding of relay SXCH, wire A2, and normally closed contact A3 of cancel button CAN, to

The dropping away of relay XCHP upon the picking up of relayEXCI-I opens the pick-up circuit for each of the change relays NCH and XCH tor prevent the interferring with the transmission of a route designated if an operator should attemptto designate a second'routc before the first route control codes have been transmitted. Andiurthermore', the dropping away of relay XCHP causes the illumination of the indicator lamp XCHE to inform the operator that the ends of a route have been` designated and such controls have notV yet been transmitted. The indicator lamp XCHE is energized by an obvious circuit closed at back contact 39 of relay XCHP. RelayjXCHP is picked up again when relay SXCH is dropped away during the transmission of a control for that eXit point and the lamp XCHE is extinguished at that time.

.The picking up of relay SXCH causes the picking up of relay CHP by' the energization of a circuit closed from (-I-l ,through a circuit including back contact AA of relay SA, back contact A5 of relay FC, upper winding of relay CHP, wire A6, and front contact 1S of relay SXCH, to Inasmuch asrelay SA is picked up during each cycle of operation, and relay CHP picks up through a back contact AA of relay SA, the picking up of relay CHP can become eiiective only during a period of rest or at the end of a cycle. When relay CHP is picked up, relay C is picked up by the energization of a circuit which has been described, and the picking up of that relay causes the pickingupv of relay 5XCD if there is no other CD relay energized, by the energization of a circuit closed fromthrough a circuit including back contact A8" of relay LV, back contact 55 of relay 2SA, front Contact 56 of relay C, back contact 5T of relay CDS, wire 58, back contact 59 of. relay SNCH, back contact 1l' of relay ANCH, aback contact of the NCH relay (not shown but represented by X) for each other 'entrance point, wire 18, front contact T9 of relay SXCI-L'lower windingof relay SXCD, wire A2, and normally closed contact A3 of cancel button CAN, to Thelp'icking' up of relay EXCD causes the picking up' of relay' 'CDS and the establishment of a stick circuit for relay EXCD by the energization of a circuit 'closed from through a circuit including front contact 6A of relay CHP (see Fig. 2C), winding of relay CDS, wire 6i, front contact 80 of relay EXCD, upper winding of relay EXCD, wire A2, and normally closed contactA3 of cancel button CAN, to The picking up of relay XCD causes the picking up of relay PC for the initiai energization of the line circuit at the beginning of the conditioning period in a manner which will be hereinafter described.

After having described how the initiation of the system is eirected in accordance with the des ignation by an operator of typical entrance and exit points, it is believed that it will be readily apparent that the circuits provided for the initiation of the system for transmission of controls designated for each entrance and exit point are provided in accordance with the typical circuits which have just been described.

As has heretofore been pointed out in a general manner, th'e relays CD and XCD are energized during the initiation of a cycle of operation in accordance with the designation of a control for that respective point, and the picking up of one relay CD or XCD causes the picking up of the relay CDS which, upon opening back contact 51, opens the pick-up circuits for all of the other CD relays and maintains such cir-cuits Open throughout the cycle of operation for which one particular CD relay has been energized. Th'us, such an arrangement of circuits provides that only one relay CD can be energized during one control cycle or at any one time. The circuits for the relays CD and XCD are also provided in such a manner that some relays CD and XCD have superiority over other relays of similar charac-ter where a plurality of NCH and XCH relays are energized at the same time for storing designated changes for the initiation of the transmission of a plurality of diierent controls. That is, for example, the picking up of relay SNCH can cause the picking up of relay 5CD in a manner which' has been described, and, relay EXCD can be picked up in a manner which has been described when relay 5XCH is picked up; but the picking up of relay 5XCD'is dependent upon the closure of back contact 11 of relay NCH and the back contact of each of the other NCH relays not shown. Therefore, if the relays NCH and 5XCH are both energized simultaneously, the picking up of relay 5NCH prevents the picking up of relay 5XCD by the opening of back contact 59, and it closes the pick-up circuit for relay CD at front contact 59, thus providing that relay ECD is energized in preference to relay EXCD under such conditions. It is believed that it will be readily apparent from the examination of the circuits for the relays CD as they have been described, that the superiority of one relay CD or XCD over the other is dependent upon the organization of the circuit network for the control of the pick-up circuits for the relays CD which provides that each relay CD or XCD having its NCH or XCH relay picked up is energized in preference to the relay CD or XCD on the right which also has its NCH or XCH relay energized.

In accordance with this general principle by which the superiority of the relays CD and XCD vary from left; to right, it is provided that all of the relays CD for the initiation of the system for the transmission of designated entrance points are superior to all of the relays XCD for the intiationvof the system in accordance with the designation of ycontrols for exit points, because such CD relays are all on the left with respect to all XCD relays. The purpose for such superiority is obviously to provide that the control for a designated entrance point is always transmitted during a cycle of operation preced- Cil ing the designation for an exit point. Such mode of operation is provided in accordance with the general principles of entrance-exit type control systems, namely, that the entrance point shall be designated rst, and the designation of an exit point subsequent to the designation of an entrance point causes a route to be established in accordance with preselecting means which is responsive to the designation of the entrance point for that route.

If an operator wishes to restore a signal to stop, or restore an entrance relay in the field which has been picked up in response to the designation of an entrance point for a particular signal, he may do so, if the entrance button NB is in a normal position with respect to rotation, by pulling the button out for that signal location, thus causing the energization of the relay NCH for that entrance point to initiate the control cycle for the transmission of the controls thus designated.

To consider more specifically how the initiation of the system is eiected under such conditions, assume that an operator 'desires to cause the transmission of a stop code for the signal 5 at a time when the normal conditions of the system exist as they have been described. The pulling out of button 5NB causes the picking up of relay ENCI-I by the energization of a circuit closed from through a circuit including contact 36 of button 5NB in a pulled out position, lower winding of relay 5NCH, wire 42, and contact 43 of cancel button CAN closed in a normal position, to The picking up of relay ENCH causes the picking up of relays CHP, C, SCD and CDS for the initiation of a control cycle by the energization of circuits similar to those which have heretofore been described.

It will be noted that initiation of a cycle for restoration is distinctive from initiation of a cycle for defining an entrance point in that the entrance relay NR for that point remains in a dropped away position to select a restoration code as is hereinafter pointed out.

Thus, in a similar manner, initiation can be effective for th'e transmission of a stop code for signal 4, and for each of the other signals included in the track layout.

If an operator has designated an entrance point by the designation of a call-on signal upon the rotation of the entrance button from its normal position, such as the rotation of the button NB in a counterclockwise direction to an operating position, the restoration of such a callon sign-al to stop can be eiective responsive to the restoration of such entrance button from its rotated operating position to its normal position with respect to rotation. Thus, if an operator restores by rotation the button 4NB to its normal position from a counterclockwise rotated position, the restoration of that button causes the energization of the relay 4NCH which in turn initiates the transmission of a control cycle in a manner which has been described. The picking up or" relay IINCH is effected while relay 4NCR is still energized, such relay 4CNR being maintained energized because of its stick circuit including front contact 12 of relay CNR. Upon the picking' up of relay NCH, however, relay CNR, is dropped away to open the pick-up circuit for the relay 4N CH and prevent further energization of that relay until designation by an operator of other controls'to be transmitted associatedV with that particular signal location.

To consider more 4specifically the initiation of "ND SlGNALS.

the system as just described in a general manner, assume that an operator restores the button 4NB to its normal position with respect to rotation from a counterclockwise operated position. When the button has reached such normal condition the closing of contact 82 or button NB causes the picking up of relay NCH by the energization of a Circuit closed from (-l-), through a circuit including contact 82 of button NB, contact 83 of button 4NB closed in its normal position, front contact l' of relay CNR, lower winding of relay ilNCH, wire a2, and normally closed contact |13 of cancel button CAN, to The picking up of relay NCH establishes a stick circuit for that relay similar to the stick circuit escribed for relay SIC-l, and the picking up of that relay also opens a stick circuit for relay QCNR at back contact l. Relay GCNP., drops away under such conditions because the other stick circuit for that relay including front contact 59 has already been opened by the rotation of the button lNB at Contact 54. Upon consideration of the stick circuits which have been described for relay ACNP. it will be apparent that the reiay riCNR has its stick circuit closed in- 1 cluding front contact 'l2 until the relay QNCH is picked up upon the restoration of the button ANB to its full normal position, thus providing that the initiation of the system for the transmission of a stop or restoration code is eiiective 1,-.

only after the button NB has been completely' restored to its normal position. Upon the dropping away of relay fiCNR, the pick-up circuit just described for relay NCH is opened at front contact 65 to prevent further picking up of the :z

relay 4NCH until another control for the entrance point at signal 4 or signal 4C has been designated. The picking up of relay JNCI-I causes the picking up of relays CHP, C, 40D and CDS for the initiation of a control cycle by the energization of circuits in the same manner to that which has already been described.

In addition to providing a means by which an operator can establish a route in accordance with the designation of entrance and exit points, it is provided that, by operation of a lever SML provided for each track switch, an operator can cause the positioning of that track switch without establishing a route and clearing a signal.

Such operation is often desirable in order to attempt to free a track switch of obstructions such as snow and ice, and is also desirable to provide a means for establishing routes which cannot be provided by the system in accordance with entrance and exit designation.

As a typical illustration of how the circuits are provided at the control oice for'the initiation of the system for the transmission of controls in accordance with the actuation of a lever SML, the circuits are shown and will be hereinafter described in detail for the lever ZSML (see Fig. 2B) associated with track switch ZTS (see Fig. 6A). The relay 2CH associated with that lever is normally energized by a circuit which has been described, and the lever 25ML is normally in its neutral position from which it can be operated by an operator to an upper reverse position or to a lower normal position.

To consider how the initiation of the system is effected upon actuation of the lever ZSML to a reverse upper position, assume that an operator, under normal conditions, actuates the lever ZSML to such a position. Such actuation causes the picking up of relay ZCI-IP by the energization of a circuit closed from through a circuit including contact 84 of lever 25ML (see Fig. 2C) in an upper position, front contact 85 of relay 2CH, and winding of relay ZCI-IP, to The picking up of relay ZGHP closes a stick circuit for that relay from (l-), through a circuit including back contact 85 of relay 2CD, front contact 87 of relay CHP, and winding of relay 23H13, to Such stick circuit causes relay ECF-EP to remain energized until relay 2CD is picked up during `the initiation of the control cycle, after which it is dropped away by the opening or" oc-.ck contact 3G.

'The picking up of relay 2CD, however, opens badi Contact in the stick circuit of relay ZCI-I to cause relay ZCH to drop away, and the dropping away of rela ECH opens the pick-up circuit for relay ZCHP at front contact 85, thus providing that ie pick-up circuit just described for relay ZGHP cannot again be closed until relay ZCI-I is again picked up, and it is further provided that relay CH cannot be picked up until the lever 25ML is operated back to its neutral position. The picking up of relay 2CHP causes the picking up of relays CHP, C, 2CD and CDS for the initiation or" a control cycle for the transmission of controls selected in accordance with the positioning of the lever 25ML. Inasmuch as relay 2CHP can be picked up only when the lever 25ML is actuated to a full normal or reverse operating position, and the initiation of the system can become eiective only when the relay ZCHP is picked up, it is believed that it will be apparent that the lever 25ML must be operated to its full normal or full reverse position before the initiation of the system for the transmission of controls becomes eiective.

It is believed apparent from the circuits just described that the actuation of the lever ZSML to a normal downward position would effect the initiation of the system in a similar manner inasmuch as contact 84 is effective for causing the energization of relay ZCI-1P When-lever 25ML is in either an upper or a lower position.

The track switch in the field positioned by an auxiliary switch control lever SNL is maintained in that position until the reception of a restoration code designated by an operator by the actuation of that SML lever to its neutral position. Thus, for example, the track switch ZTS operated to a reverse position in accordance with the positioning of lever ZSML is maintained in that position until a restoration control is received in accordance with an operator actuating the auxiliary lever 23ML to its neutral position.

To consider how a control cycle is initiated responsive to the restoration of an auxiliary lever to its center neutral position, assume that an operator restores the lever 25ML from its upper reverse position `to its neutral position, after controls have been transmitted to the field in accordance with the reverse position of that lever. The actuation of the lever ZSML to its neutral position from its upper reverse position causes the picking up of relay ECI-IP for the initiation of the control cycle by the energization of a circuit closed from through a circuit including Contact 84 of lever 25ML in a neutral position, back contact 35 of relay 20H, and winding of relay ZCHP, to The picking up of relay ZGHP closes the initiation of the system for the transmission of a control cycle.

Upon the picking up of relay ZCI-1P, under such conditions, a pick-up circuit is closed for relay ZCH from (-1-) through a circuit including contact 84 of lever 25ML in a neutral position, front 

